Journal of Cardiovascular Magnetic Resonance最新文献

Background: Fabry disease (FD) is an X-linked inherited lysosomal storage disease that is caused by deficient activity of the enzyme alpha-galactosidase A. Cardiovascular magnetic resonance (CMR) imaging can detect cardiac sphingolipid accumulation using native T1 mapping. The kidneys are often visible in cardiac CMR native T1 maps; however, it is currently unknown if the maps can be used to detect sphingolipid accumulation in the kidneys of FD patients. Therefore, the aim of this study was to evaluate if cardiac-dedicated native T1 maps can be used to detect sphingolipid accumulation in the kidneys.

Methods: FD patients (n = 18, 41 ± 10 years, 44% (8/18) male) and healthy subjects (n = 38, 41 ± 16 years, 47% (18/38) male) were retrospectively enrolled. Native T1 maps were acquired at 1.5T using modified Look-Locker inversion recovery research sequences. Native T1 values were measured by manually delineating regions of interest (ROI) in the renal cortex, renal medulla, heart, spleen, blood, and liver. Endo- and epicardial borders were delineated in the myocardium and averaged across all slices. Blood ROIs were placed in the left ventricular blood pool in the midventricular slice.

Results: There were no differences in native T1 between the FD patients and the healthy subjects in the renal cortex (1034 ± 88 ms vs 1056 ± 59 ms, p = 0.29), blood (1614 ± 111 ms vs 1576 ± 100 ms, p = 0.22), spleen (1143 ± 45 ms vs 1132 ± 70 ms, p = 0.54), or liver (568 ± 49 ms vs 557 ± 47 ms, p = 0.41). Native myocardial T1 was lower in FD patients compared to healthy subjects (951 ± 79 vs 1006 ± 38, p<0.01), and higher in the renal medulla (1635 ± 144 vs 1514 ± 81, p<0.01).

Conclusion: Compared to healthy subjects, patients with FD and cardiac involvement showed no differences in native T1 of the renal cortex. FD patients had higher native T1 in the renal medulla, which is not totally explained by differences in blood native T1 but may reflect a hyperfiltration state in the development of renal failure. The findings suggest that sphingolipid accumulation in the renal cortex in FD patients could not be detected with cardiac-dedicated research native T1 maps.

Background: Right ventricular (RV) dyssynchrony or post systolic contraction (PSC) causes inefficient pumping and has not been investigated as a prognostic marker in pulmonary arterial hypertension (PAH). The objective was to investigate if RV dyssynchrony and PSC are prognostic markers of transplantation-free survival in PAH and if multiple RV views improve prognostication.

Methods: Patients with PAH undergoing cardiovascular magnetic resonance between 2003 and 2021 were included. For strain analysis, endocardial end-diastolic RV contours were delineated in RV three-chamber (RV3ch), four-chamber (4ch), and midventricular short-axis (SAX) slice. RV dyssynchrony was defined as the standard deviation of time to peak strain in the walls from one (4ch), two (4ch and SAX), or three views (4ch, SAX, and RV3ch). PSC was defined as peak strain occurring after pulmonary valve closure. Outcome was defined as death or lung transplantation.

Results: One hundred and one patients (58 ± 19 years, 66% (67/101) women) were included. Median follow-up was 37 [51] months. There were 60 events (55 deaths and 5 lung transplantations). Outcome was associated with RV dyssynchrony from three views and with RV strain in 4ch. An increase in RV dyssynchrony-in three views-by 1% was associated with a 10% increased risk of lung transplantation or death. There was no association between outcome and RV dyssynchrony in one or two views nor with PSC.

Conclusion: RV dyssynchrony in three views was associated with outcome in PAH, whereas assessing dyssynchrony from one or two views and PSC was not. This implies that assessment of multiple instead of single RV views could potentially be used for prognostication in PAH.

Aims: Myocardial inflammation is increasingly detected noninvasively by tissue mapping with cardiovascular magnetic resonance (CMR). Intraindividual agreement with endomyocardial biopsy (EMB) or markers of myocardial injury, high-sensitive cardiac troponin (hs-cTnT) in patients with clinically suspected viral myocarditis is incompletely understood.

Methods: Prospective multicenter study of consecutive patients with clinically suspected myocarditis who underwent blood testing for hs-cTnT, CMR, and EMB as a part of diagnostic workup. EMB was considered positive based on immunohistological criteria in line with the European Society of Cardiology (ESC) definitions. CMR diagnoses employed tissue mapping using sequence-specific cut-off for native T1 and T2 mapping; active inflammation was defined as T1 ≥2 standard deviation (SD) and T2 ≥2 SD above the mean of normal range. Hs-cTnT of greater than 13.9 ng/L was considered significant.

Results: A total of 114 patients (age (mean ± SD) 54 ± 16, 65% males) were included, of which 79 (69%) had positive EMB criteria, 64 (56%) CMR criteria, and a total of 58 (51%) positive troponin. Agreement between EMB and CMR diagnostic criteria was poor (CMR vs ESC: area under the curve (AUC): 0.51 (0.39-0.62)). The agreement between a significant hs-cTnT rise and CMR-based diagnosis of myocarditis was good (AUC: 0.84 (0.68-0.92); p < 0.001), but poor for EMB (0.50 (0.40-0.61). Hs-cTnT was significantly associated with native T1 and T2, high-sensitive C-reactive protein, and N-terminal pro-hormone brain natriuretic peptide (r = 0.37, r = 0.35, r = 0.30, r = 0.25; p < 0.001), but not immunohistochemical criteria or viral presence.

Conclusion: In clinically suspected viral myocarditis, all diagnostic approaches reflect the pathophysiological elements of myocardial inflammation; however, the differing underlying drivers only partially overlap. The EMB and CMR diagnostic algorithms are neither interchangeable in terms of interpretation of myocardial inflammation nor in their relationship with myocardial injury.

Background: To investigate the ability of a delayed respiratory-navigated, electrocardiographically-gated three-dimensional inversion recovery-prepared fast low-angle shot (3D IR FLASH) sequence to evaluate the lower airways in children undergoing routine cardiovascular magnetic resonance (CMR).

Methods: This retrospective study included pediatric patients (0-18 years) who underwent clinical CMR where a delayed 3D IR FLASH sequence was performed between July 2020 and April 2021. The airway image quality and extent of lower airway visibility were graded by two blinded readers using a four-point ordinal scale (0-3). Lower airway anatomical variants and abnormalities were recorded.

Results: One hundred and eighty patients were included with a median age of 11.7 (4.6-15.3) years. Fifty-one of 180 (28%) were under general anesthesia. Overall, the median grading of airway image quality was 3 (2-3) and the extent of lower airway visibility was 3 (3-3). Interrater agreement was almost perfect (κ = 0.867 and κ = 0.956, respectively). Image quality correlated with extent of lower airway visibility (r = 0.62, p < 0.01). Delayed 3D IR FLASH was able to characterize the segmental bronchi in 137/180 (76%) and lobar bronchi in 172/180 (96%) of patients. Lower airway abnormalities were identified in 37/180 (21%) of patients and 33/129 (26%) with congenital heart disease (CHD). Identified abnormalities included tracheobronchial branching anomalies in 6/180 (3%), abnormal tracheobronchial situs in 6/180 (3%), and extrinsic vascular compression in 25/180 (14%).

Conclusion: Delayed 3D IR FLASH has excellent performance for evaluation of the lower airway anatomy and can simultaneously assess for myocardial late gadolinium enhancement. Lower airway abnormalities are not infrequently seen in children undergoing routine CMR for CHD.

Background: Aortic dilation is seen in pediatric/young adult patients with bicuspid aortic valve (BAV), and hemodynamic markers to predict aortic dilation are necessary for monitoring. Although promising hemodynamic metrics, such as abnormal wall shear stress (WSS) magnitude, have been proposed for adult BAV patients using four-dimensional (4D) flow cardiovascular magnetic resonance, those for pediatric BAV patients have less frequently been reported, partly due to scarcity of data to define normal WSS range. To circumvent this challenge, this study aims to investigate if a recently proposed 4D flow-based hemodynamic measurement, abnormal flow directionality, is associated with aortic dilation in pediatric/young adult BAV patients.

Methods: 4D flow scans for BAV patients (<20 years old) and age-matched controls were retrospectively enrolled. Static segmentation for the aorta and pulmonary arteries was obtained to quantify peak systolic hemodynamics and diameters in the proximal aorta. In addition to peak velocity, WSS, vorticity, helicity, and viscous energy loss, direction of aortic velocity and WSS in BAV patients were compared with that of control atlas using registration technique; angle differences of >60 deg and >120 deg were defined as moderately and severely abnormal, respectively. The association between the obtained metrics and normalized diameters (Z-scores) was evaluated at the sinotubular junction, mid-ascending aorta, and distal ascending aorta.

Results: Fifty-three BAV patients, including 18 with history of repaired aortic coarctation, and 17 controls were enrolled. Correlation between moderately abnormal velocity/WSS direction and aortic Z-scores was moderate to strong at the sinotubular junction and mid-ascending aorta (R = 0.62-0.81; p < 0.001) while conventional measurements exhibited weaker correlation (|R| = 0.003-0.47, p = 0.009-0.99) in all subdomains. Multivariable regression analysis found moderately abnormal velocity direction and existence of aortic regurgitation (only for isolated BAV group) were independently associated with mid-ascending aortic Z-scores.

Conclusion: Abnormal velocity and WSS directionality in the proximal aorta were strongly associated with aortic Z-scores in pediatric/young adult BAV patients.

Background: Aerobic exercise capacity is an independent predictor of mortality in dilated cardiomyopathy (DCM), but the central mechanisms contributing to exercise intolerance in DCM are unknown. The aim of this study was to characterize coronary microvascular function in DCM and determine if cardiovascular magnetic resonance (CMR) measures are associated with aerobic exercise capacity.

Methods: Prospective case-control comparison of adults with DCM and matched controls. Adenosine-stress perfusion CMR to assess cardiac structure, function and automated inline myocardial blood flow quantification, and cardiopulmonary exercise testing to determine peak VO₂ was performed. Pre-specified multivariable linear regression, including key clinical and cardiac variables, was undertaken to identify independent associations with peak VO₂.

Results: Sixty-six patients with DCM (mean age 61 years, 47 male) were propensity-matched to 66 controls (mean age 59 years, 47 male) based on age, sex, body mass index, and diabetes. DCM patients had markedly lower peak VO₂ (19.8 ± 5.5 versus 25.2 ± 7.3 mL/kg/min; P < 0.001). The DCM group had greater left ventricular (LV) volumes, lower systolic function, and more fibrosis compared to controls. In the DCM group, there was similar rest but lower stress myocardial blood flow (1.53 ± 0.49 versus 2.01 ± 0.60 mL/g/min; P < 0.001) and lower myocardial perfusion reserve (MPR) (2.69 ± 0.84 versus 3.15 ± 0.84; P = 0.002). Multivariable linear regression demonstrated that LV ejection fraction, extracellular volume fraction, and MPR, were independently associated with percentage-predicted peak VO₂ in DCM (R² = 0.531, P < 0.001).

Conclusion: In comparison to controls, DCM patients have lower stress myocardial blood flow and MPR. In DCM, MPR, LV ejection fraction, and fibrosis are independently associated with aerobic exercise capacity.

Background: Strain analysis offers a valuable tool to assess myocardial mechanics, allowing for the detection of impairments in heart function. This study aims to evaluate the pattern of myocardial strain in patients with heart failure (HF).

Methods: In the present study, myocardial strain was measured by cardiac magnetic resonance imaging feature tracking in 35 control subjects without HF and 195 HF patients. The HF patients were further categorized as HF with preserved ejection fraction (HFpEF, n = 80), with mid-range ejection fraction (HFmrEF, n = 34), and with reduced ejection fraction (HFrEF, n = 81). Additionally, quantitative tissue evaluation parameters, including native T1 relaxation time and extracellular volume (ECV), were examined.

Results: Compared to controls, patients in all HF groups (HFpEF, HFmrEF, and HFrEF) demonstrated impaired left ventricular (LV) strains and systolic and diastolic strain rates in all three directions (radial, circumferential, and longitudinal) (p < 0.05 for all). LV strains also showed significant correlations with LV ejection fraction and brain natriuretic peptide levels (p < 0.001 for all). Notably, septal contraction was significantly affected in HFpEF compared to controls. While LV torsion was slightly increased in HFpEF, it was decreased in HFrEF. Native T1 relaxation times and ECV fractions were significantly higher in HFrEF compared to HFpEF (p < 0.05). Overall, myocardial strain parameters demonstrated good performance in differentiating HF categories.

Conclusions: The myocardial strain impairments exhibit a spectrum of severity in patients with HFpEF, HFmrEF, and HFrEF compared to controls. Assessment of myocardial mechanics using strain analysis may offer a clinically useful tool for monitoring the progression of systolic and diastolic dysfunction in HF patients.

Background: Cardiovascular magnetic resonance imaging (CMR) faces challenges due to the interference of bright fat signals in visualizing structures, such as coronary arteries. Effective fat suppression is crucial, especially when using whole-heart CMR techniques. Conventional methods often fall short due to rapid fat signal recovery, leading to residual fat content hindering visualization. Water-selective off-resonant radiofrequency (RF) pulses have been proposed but come with tradeoffs between pulse duration, which increases scan time, and increased RF energy deposit, which limits their applicability due to specific absorption rate (SAR) constraints. The study introduces a lipid-insensitive binomial off-resonant (LIBOR) RF pulse, which addresses concerns about SAR and scan time, and aims to provide a comprehensive quantitative comparison with published off-resonant RF pulses for CMR at 3T.

Methods: A short (1 ms) LIBOR pulse, with reduced RF power requirements, was developed and implemented in a free-breathing respiratory-self-navigated three-dimensional radial whole-heart CMR sequence at 3T. A binomial off-resonant rectangular (BORR) pulse with matched duration, as well as previously published lipid-insensitive binomial off-resonant excitation (LIBRE) pulses (1 and 2.2 ms), were implemented and optimized for fat suppression in numerical simulations and validated in volunteers (n = 3). Whole-heart CMR was performed in volunteers (n = 10) with all four pulses. The signal-to-noise ratio (SNR) of ventricular blood, skeletal muscle, myocardium, and subcutaneous fat and the coronary vessel detection rates and sharpness were compared.

Results: Experimental results validated numerical findings and near-homogeneous fat suppression was achieved with all four pulses. Comparing the short RF pulses (1 ms), LIBOR reduced the RF power nearly two-fold compared with LIBRE, and three-fold compared with BORR, and LIBOR significantly decreased overall fat SNR from cardiac scans, compared to LIBRE and BORR. The reduction in RF pulse duration (from 2.2 to 1 ms) shortened the whole-heart acquisition from 8.5 to 7 min. No significant differences in coronary arteries detection and sharpness were found when comparing all four pulses.

Conclusion: LIBOR pulses enabled whole-heart CMR under 7 min at 3T, with large volume fat signal suppression, while reducing RF power compared with LIBRE and BORR pulses. LIBOR is an excellent candidate to address SAR problems encountered in CMR sequences where fat suppression remains challenging and short RF pulses are required.

Background: Metabolic diseases can negatively alter epicardial fat accumulation and composition, which can be probed using quantitative cardiac chemical shift encoded (CSE) cardiovascular magnetic resonance (CMR) by mapping proton-density fat fraction (PDFF). To obtain motion-resolved high-resolution PDFF maps, we proposed a free-running cardiac CSE-CMR framework at 3T. To employ faster bipolar readout gradients, a correction for gradient imperfections was added using the gradient impulse response function (GIRF) and evaluated on intermediate images and PDFF quantification.

Methods: Ten minutes free-running cardiac 3D radial CSE-CMR acquisitions were compared in vitro and in vivo at 3T. Monopolar and bipolar readout gradient schemes provided 8 echoes (TE1/ΔTE = 1.16/1.96 ms) and 13 echoes (TE1/ΔTE = 1.12/1.07 ms), respectively. Bipolar-gradient free-running cardiac fat and water images and PDFF maps were reconstructed with or without GIRF correction. PDFF values were evaluated in silico, in vitro on a fat/water phantom, and in vivo in 10 healthy volunteers and 3 diabetic patients.

Results: In monopolar mode, fat-water swaps were demonstrated in silico and confirmed in vitro. Using bipolar readout gradients, PDFF quantification was reliable and accurate with GIRF correction with a mean bias of 0.03% in silico and 0.36% in vitro while it suffered from artifacts without correction, leading to a PDFF bias of 4.9% in vitro and swaps in vivo. Using bipolar readout gradients, in vivo PDFF of epicardial adipose tissue was significantly lower compared to subcutaneous fat (80.4 ± 7.1% vs 92.5 ± 4.3%, P < 0.0001).

Conclusions: Aiming for an accurate PDFF quantification, high-resolution free-running cardiac CSE-MRI imaging proved to benefit from bipolar echoes with k-space trajectory correction at 3T. This free-breathing acquisition framework enables to investigate epicardial adipose tissue PDFF in metabolic diseases.